LONG-TERM RESULTS AND LATE COMPLICATIONS AFTER INTRACAVITARY YTTRIUM-90 COLLOID IRRADIATION OF RECURRENT CYSTIC CRANIOPHARYNGIOMAS

OBJECTIVE

Data were analyzed to assess the value of stereotactically applied intracystic colloidal yttrium-90 (YTx) for the treatment of recurrent cystic craniopharyngiomas during a 30-year period.

METHODS

This article compares data from 73 YTx procedures in 60 patients between 1975 and 2006. The cumulative beta dose aimed at the inner surface of the cyst wall was 300 Gy.

RESULTS

After YTx, the initial cyst volumes decreased an average of 79%. In 47, the reduction was more than 80%; in 27 of them, the cyst disappeared completely within 1 year. The mean survival after YTx was 9.4 years (range, 0.7–30 yr). Actuarial survival rates at 5, 10, 15, 20, 25, and 30 years were 81, 61, 45, 18, 2, and 0%, respectively. Late complications of YTx were related to the anatomic localization of the cyst, either presellar and retrosellar, e.g., a presellar (prechiasmatic/suprasellar) localization caused neuro-ophthalmological complications in 5.8% and internal carotid artery injury in 1.6%. The treatment of retrosellar (retrochiasmatic, suprasellar) tumors occasionally induced hypothalamic and/or pontomesencephalothalamic damage obviously by untoward radiation to the so-called perforating arteries. This occurred in 3.2% of these latter patients.

CONCLUSION

Despite sporadic complications, intracavitary YTx irradiation is a valuable treatment alternative for craniopharyngioma cysts, sometimes as part of a multimodality management in these tumors, especially in precarious surgical cases.

Tissue response to iodine-125 interstitial brachytherapy of cerebral gliomas

The purpose of this study was to investigate histopathological changes and the role of the microglia/macrophage cell system in the therapeutic effect of iodine-125 (125I) interstitial brachytherapy on cerebral gliomas. Out of a series of 60 cases harboring cerebral astrocytomas and other brain tumors treated with 125I interstitial brachytherapy, autopsy material was available in 10 cases between 0.75 and 60 months after irradiation. The patients were treated with 60-Gy maximum doses at the tumor periphery. Besides the routine HE and Mallory's PTAH trichrome staining, immunohistochemical reactions were carried out for CD15, CD31, CD34, CD45, CD68 (PG-M1), CPM, HAM 56 and HLA-DR antigens to study immunological characteristics of the reactive cell population around gliomas after 125I treatment. The present immunohistochemical study demonstrated that the early lesions following 125I interstitial brachytherapy of gliomas are characterized by migrating macrophages apparently concerned with the removal of necrotic debris. The established phase of reactive zone around the necrotic center disclosed a narrow inner rim of microglial accumulation, and a broad outer area consisting of astrocytic gliosis, vascular proliferation, activated microglia and infiltration by macrophages. In the burned-out phase, the necrosis undergoes liquefaction, the microglial rim is replaced by end-stage macrophages, and the reactive zone is transformed into astrocytic gliosis, which can be considered as equivalent to scar tissue formed around necrosis outside of the central nervous system.

Image fusion-guided stereotactic iodine-125 interstitial irradiation of inoperable and recurrent gliomas

Between 1996 and 2004, 27 patients with low grade gliomas (WHO grade I-II), 10 patients with WHO grade III gliomas and 6 patients with glioblastoma multiforme (WHO grade IV) were treated with stereotactic brachytherapy using low-dose rate iodine-125 (125I) isotope seeds at the Department of Neurosurgery, St. John's Hospital, Budapest, Hungary. In all 43 cases, brachytherapy was used for surgically inoperable gliomas: in 32 cases for recurrent gliomas and in 11 cases as a primary treatment. Results of this study suggest that 125I brachytherapy for inoperable and recurrent gliomas is an effective method and offers a chance for longer-term survival.

Stereotactic intracavitary irradiation of cystic craniopharyngiomas with yttrium-90 isotope

The authors analyzed data from nearly 30-year follow-up period to assess the value of intracavitary irradiation with stereotactically implanted beta-emitting radioisotope yttrium- 90 (90Y) silicate colloid for the treatment of cystic craniopharyngiomas. Seventy-three cysts in 60 patients were selected for retrospective analysis. The cumulative dose aimed at the inner surface of the cyst wall was 300 Gy. An average of 79% (mean 88.3%) shrinkage of the initial cyst volume was observed. In 47 cysts, the reduction was more than 80%, and the cyst disappeared totally in 29 out of those 47 cases, usually within a year. Mean survival duration after intracavitary irradiation was 9.4 years. Neuroophthalmological prognosis was only favorable when the optic disc was normal or nearly normal at the time of the treatment. In the presence of preexisting optic atrophy, visual damage proved to be irreversible. The long-term results support the view that intracavitary 90Y irradiation is a noninvasive and effective method for the treatment of craniopharyngioma cysts. Because of the mean penetration pathway of beta irradiation is 3.6mm in the soft tissues (maximum 11 mm) it cannot influence the solid part of the tumor; therefore, the best result can be expected in solitary cysts.

Pathological findings in cystic craniopharyngiomas after stereotactic intracavitary irradiation with yttrium-90 isotope

Histopathological, ultrastructural and polyacrylamide gel electrophoretic examinations were carried out on biopsy, cyst fluid, surgical pathology and autopsy specimens obtained from 7 cystic craniopharyngioma cases before and after yttrium-90 silicate colloid (90Y) irradiation. Light microscopy revealed that the lining epithelial tumor cell layer of the cyst wall was destroyed, and scar tissue containing large amount of hyaline degenerated collagen bundles replaced it. Proliferative postirradiation vasculopathy was also demonstrated in the cyst wall following 90Y installation. Electrophoretic property of cyst fluid was similar to the normal human serum. Considering that scar tissue has a certain propensity to shrink, the fibrosis in the cyst wall together with destruction of neoplastic epithelium and vascular changes might explain diminished fluid production and cyst volume reduction after 90Y treatment.

Review of Radiosurgery of Pineal Parenchymal Tumors. Long Survival Following 125-Iodine Brachytherapy of Pineoblastomas in 2 Cases

OBJECTIVE

The aim of the present work is to report the volumetric changes of tumor in two pineoblastoma patients treated with stereotactic interstitial irradiation and to present a review on radiosurgery of pineal parenchymal tumors.

METHODS

Two of our patients with pineoblastoma were treated with CT and image-fusion guided 125-iodine brachytherapy. The tumor volumes were determined with outlined contours on planning and control CT/MRI images and were compared.

RESULTS

Until January 2006, there were 61- and 58-month follow-up periods in the two cases. 56 and 53 months after irradiation the MRI images showed significant tumor shrinkage. In case 1 tumor volume was 0.76 cm (3) on the last control MRI image, compared to the 2.87 cm (3) at the time of interstitial irradiation, which means 73% shrinkage. In case 2, tumor volume measured with the last control MRI examination was 0.29 cm (3), which represents 77% shrinkage of the original tumor volume. In both Cases 1 and 2, PET examinations using (11)C-methionine showed no active tumor mass 56 and 53 months following brachytherapy.

CONCLUSION

Two successful treatments of pineoblastoma are reported. The interstitial irradiation of the tumors decreased their volumes significantly. The CT and image fusion-guided 125-iodine stereotactic brachytherapy can be planned well dosimetrically and is surgically precise.

Iodine-125 brachytherapy of brain stem tumors

PURPOSE

To report on iodine-125 ((125)I) interstitial irradiation in the treatment of brain stem tumors.

PATIENTS AND METHODS

Two patients with brain stem tumors were treated with CT- and image fusion-guided (125)I stereotactic brachytherapy.

RESULTS

By March 2003, the patients had been followed up for 47 and 13 months, respectively. In case 1, the tumor volume was 1.98 cm(3) on the control CT, indicating a 65.5% shrinkage as compared to a target volume of 5.73 cm3 at the time of brachytherapy. In case 2, shrinkage was more distinct. After irradiation, the cyst volume was 0.16 cm(3) on the control MRI, indicating a 97.4% shrinkage as compared to a target volume of 6.05 cm(3) at the time of brachytherapy, i. e., the metastasis had virtually disappeared.

CONCLUSION

CT- and image fusion-guided (125)I stereotactic brachytherapy can be performed during the biopsy session. The procedure can be well planned dosimetrically and is surgically precise.

Brachytherapy of Vestibular Schwannomas: Report of Three Cases

OBJECTIVE

Gamma knife and multileaf collimator LINAC have recently gained notoriety in the treatment of vestibular schwannomas. Without the use of gamma knife or LINAC, we have successfully pursued the 125-iodine interstitial irradiation of three vestibular schwannomas.

CASE REPORT

Up to March 2004, there was a 57 and 45 month follow-up period in two cases. One patient died of heart insufficiency 15 months after the brachytherapy. At the end of the follow-up period audiometric examinations revealed slight improvements of hearing in patients 1 and 2. In patient 1, the tumor volume measured was 4.06 mL on the control CT indicating a 40 % shrinkage in comparison to the 6.74 mL target volume at the brachytherapy. In patient 2, the tumor volume measured on the control MRI was 6.64 mL, indicating a 42 % shrinkage of the 11.45 mL target volume at the time of brachytherapy. Eleven months after the brachytherapy in patient 3 we found 10 % tumor shrinkage, a post-irradiation cyst developed inside the tumor and reached up to 35 % of the tumor volume.

INTERVENTION

In the treatment of three vestibular schwannomas we have used CT and image-fusion guided 125-iodine stereotactic brachytherapy.

CONCLUSION

Due to financial considerations, gamma knife and LINAC are not available for many countries and neurosurgical institutes. In the absence of the above-mentioned radiosurgical methods, we have shown brachytherapy as a new alternative and solution in the treatment of the three patients studied with vestibular schwannoma.

[Brachytherapy of brainstem tumors]

INTRODUCTIONS

The optimal therapy of brain stem tumours of different histopathology determines the expected length of survival. Authors report 125Iodine interstitial irradiation of brain stem tumours with stereotactic brachytherapy.

CASE REPORTS

Two patients having brain stem tumours were suffering from glioma or from metastases of a carcinoma. In Case 1 the tumour volume was 1.98 cm3 at the time of planning interstitial irradiation. The control MRI examination performed at 42 months post-op showed a postirradiation cyst size of 5.73 cm3 indicating 65.5% shrinkage. In Case 2 the shrinkage was more apparent as the tumour volume measured on the control MRI at 8 months post-op was only 0.16 cm3 indicating 97.4% shrinkage of the 6.05 cm3 target volume at the time of brachytherapy with the metastasis practically disappearing. Quick access to histopathological results of the stereotactic intraoperative biopsy made it possible to carry out the 125Iodine stereotactic brachytherapy immediately after the biopsy, resulting in less inconvenience for patients of a second possible intervention. The control MRI scans show significant shrinkage of tumours in both patients.

CONCLUSION

The procedure can be performed as a biopsy. The CT and image fusion guided 125Iodine stereotactic brachytherapy can be well planned dosimetrically and is surgically precise.

[Interstitial boost and altered fractionation as novel approaches to dose escalation in the radiotherapy of glioblastoma multiforme]

INTRODUCTION

The practice of image-based three dimensional treatment planning and conformal radiotherapy techniques give the opportunity to elaborate optimal treatment forms for primary brain tumours.

PURPOSE

The authors examined the effect of two novel dose escalation methods on glioblastoma patients.

METHODS

In nine cases they treated T1 tumours with single HDR-AL boost of 10-12 Gy dose following the conventional fractionated 60 Gy external beam radiotherapy. In fifteen patients with T2-4 tumours an intensified, hypofractionated regimen with 2.25-2.5 Gy daily and 60 Gy total dose was applied. All the treatments were carried out with image-based conformal methods.

RESULTS

Majority of patients endured treatments without neurological deterioration. Transient neurotoxiticy was noticed in one and two cases, respectively. The median survival times (MST) were found to be 17 months (range: 9-25) and 12 months (range: 6-38) in the two groups, respectively. With respect to all patients, the MST was 13 months, while this value in the conventional treatment is generally considered to be 9-10 months. All the three patients who survived more than 18 months was treated with temozolamide chemotherapy as well.

CONCLUSION

Based on own experience and current knowledge of authors, it seems reasonable to apply higher biological dose focal radiotherapy and chemotherapy in case of glioblastoma patients with better prognosis. To define the optimal treatment regimens randomised clinical trials should be executed.

[Movement-activated [15O]-butanol PET scan in patients with Parkinson disease]

The regional cerebral perfusion has been studied by [15O]-butanol PET in bradykinetic patients with Parkinson's disease. In comparison with the rest condition significantly higher perfusion was detected in the primary sensorimotor cortex, parietal cortex, premotor cortex and supplementary motor area. A decrease of activity was observed in the lateral motor cortex, medial frontal cortex, dorsolateral prefrontal cortex and bilaterally in the head of the caudate nuclei. The method is capable of demonstrating the reorganisation of extrapyramidal movement regulation and the impact of medical and surgical treatment modalities. Based on the results conclusions can be drawn for the modes of action of the different treatment modalities.

CT-guided unilateral thalamotomy with macroelectrode mapping for the treatment of Parkinson's disease

OBJECTIVE

To evaluate the effect of unilateral thalamotomy in patients with Parkinson's disease.

METHODS

The junction of the ventralis oralis posterior and ventralis intermedius nuclei targeted under CT-guidance, and confirmed by impedance recording and macrostimulation.

RESULTS

At the 6-month assessment the tremor has been completely abolished in 37 patients (82.2%), and reduced in 6 patients (13.3%). The Unified Parkinson's Disease Rating Scale tremor score decreased by 92.5%, rigidity improved by 65.9%. Axial symptoms and bradykinesia showed smaller improvement. The levodopa and anti-cholinergic medication significantly reduced. An improvement in the quality of life measured by the Parkinson's Disease Questionnaire (PDQ-39) has been observed. The dimensions of mobility, activities of daily living, emotional well being, and stigma were significantly (P<0.05) better, other changes were not significant. The single index improved from 47.8+/-7.8 to 28.9+/-6.3. Transient complications noted in 9 patients (20%), mild persistent morbidity observed in 3 patients (6.7%). At the 1, 2 and 3-year follow-up neither contralateral tremor, rigidity, nor bradykinesia progression was statistically significant.

CONCLUSIONS

CT-guided thalamotomy with macro-electrode mapping provides a safe, effective and long lasting control of tremor and rigidity, reduces the need for medication, and improves the quality of life.

The application of image fusion in stereotactic brachytherapy of brain tumours

BACKGROUND

The visualization of any morphological volume (i.e. CT, MRI) together with an additional second morphological volume (i.e. CT, MRI) or functional data set, which may come from SPECT or PET, is a new method for treatment planning, verification and follow-up of interstitial irradiation.

METHOD

The authors present their experience on interstitial irradiation of brain tumours with stereotactically implanted I-125 seeds supported by image fusion. The image fusion was performed by the BrainLab-Target 1.13 software on Alfa 430 (Digital) workstation before, during, and after interstitial irradiation of brain tumours with Iodine125 seeds.

RESULTS AND INTERPRETATION

On the basis of 20 brachytherapeutic image fusion of stereotactic CT (slices with fiducials) with additional stereotactic CT, MRI, PET and SPECT images provides more accurate and precise target volume, more exact localization of catheters and isotope seeds (verification fusion), differentiation between the localization and amount of the necrotic and proliferating parts of the tumours and shows the volume changes in consequence of interstitial irradiation. The image fusion should help to improve the accuracy and minimize the perifocal morbidity of interstitial irradiation.

[CT- and MRI-guided conformal interstitial and external beam radiotherapy of primary brain tumors: prospects in Hungary]

The technical improvements gained over the last decade in neuroradiology and radiotherapy have brought significant theoretical and experimental changes in the treatment of primary glial brain tumours. The follow-up of patients with CT, MRI and isotope diagnostic examinations proves that the relapses take place in the vicinity of the primary site in most cases. Consequently, the conventional large fields or whole brain irradiation techniques have been phased out and the conformal irradiation methods focused on the tumorous targets have gained ground. The exact neuroanatomic projection, the image based 3-dimensional treatment planning methods and the conformal irradiation techniques ensure that only the tumorous or the potentially infiltrated regions become irradiated with maximal protection of the normal brain tissues. The increased protection of the normal tissues makes a dose escalation possible, which may result in the augmentation of the therapeutic benefits. In Hungary both the interstitial and the external beam conformal radiotherapies of the CNS have become accessible in practice over the recent years. In possession of manifold treatment modalities (percutaneous fractionated conformal radiotherapy, stereotactic radiosurgery, high dose rate after-loading and low dose rate interstitial irradiation), it is found necessary to overview the indicative territories, advantages, limitations and possible complications of different interventions. The authors describe the possible routes of further improvements and ways of dose escalation. Nevertheless, it is emphasised that gliomas--with reduced radiosensitivity and high potential to infiltrate the adjacent brain tissues-represent the illness in the whole CNS. It implies that in the future it will probably be necessary to initiate systemic therapeutic modalities in the course of routine treatment strategies in addition to the focused and more effective radiotherapy regimens.

Treatment of cystic craniopharyngiomas with yttrium-90 colloid solution

The authors analyzed long-term follow-up data to assess the value of intracavitary irradiation with stereotactically implanted beta-emitting radioisotope (90)Y-silicate colloid for the treatment of craniopharyngiomas. Fifty-seven craniopharyngiomas in 42 patients were selected for retrospective analysis. The yttrium-90 was implanted intracavitally, using computerized tomography-guided and three-dimensional stereotactic treatment planning. The cumulative dose aimed at the inner surface of the cyst wall was 300 Gy. An average of 75% shrinkage of the initial cyst volume was observed. In 18 cases the reduction was more than 91%, and the cyst disappeared totally in 11 cases. A 50% decrease in cyst volume was usually apparent between the 2nd and 4th months. A 70% decrease in cyst volume was seen by the 5th and 6th months and an 80% reduction by the 7th and 8th months. Cysts that were unchanged remained so throughout the observation period. The time course of volume reduction could be expressed mathematically by the formula of 0.73 X e(-0.62 X T) + 0.27, where "e" is the basic number of natural logarithm and "T" is the time expressed in months. Mean survival duration after intracavitary irradiation was 9.4 years. The shrinkage of the cyst was a consequence of fibrosis of the wall, as seen on histopathological examination. The neuroophthalmological prognosis was favorable only when the optic disc was normal or nearly normal at the time of the treatment. In the presence of preexisting optic atrophy, visual deterioration proved to be irreversible. The long-term results support the view that intracavitary (90)Y-irradiation is a noninvasive and very effective method of treatment for craniopharyngioma cysts. Because of the 1.1 mm half-life decay of beta irradiation, it cannot influence the solid part of the tumor; therefore, the best result can be expected in solitary cysts.

Posterior fossa haemangioblastomas

36 consecutive years' experience in treating 104 cases of posterior fossa haemangioblastomas is described and discussed. The mortality was 24%, with a tendency to decrease, reaching 20% in the last 15 years. About half the patients returned to neurological normality and full working capacity. Dividing the lesions into solid and cystic tumours, cystic tumours were more frequent, their survival was longer, recurrence less and postoperative state somewhat better.

Secretory component of cystic craniopharyngiomas: a mucino-histochemical and electron-microscopic study

Ten cases with cystic craniopharyngioma were investigated. Histologically, eight of them belonged to the adamantinomatous group and two were squamous epithelial type. Histochemical investigation revealed mucin secretion in microcysts, and electron microscopy demonstrated zymogen granules in the epithelial cells. When the protein content of the cyst fluid was analyzed by polyacrylamide-gel electrophoresis, the electrophoretic pattern and immunological properties were found to be similar to the normal human serum control. The results of the morphological study suggest that cystic craniopharyngiomas have a secretory component in addition to the classical histological structures.

Pathological changes in cystic craniopharyngiomas following intracavital 90yttrium treatment

Radiosurgery, using 90Y injected directly into the cavity of cystic craniopharyngiomas produces remarkable reduction of tumour size and diminishes cyst fluid production. The authors have studied the histology of biopsy and autopsy material obtained from seven patients presented with cystic craniopharyngiomas. Histological examination was carried out before and after 90Y silicate implantation. As an effect of 90Y irradiation, histology of samples taken from the cyst wall revealed that the lining epithelial cell layer became destroyed and the cyst wall shrunk. Large amount of collagen fibres with focal hyaline degeneration was present. Proliferation of intimal cells and subendothelial connective tissue narrowing small vessel lumina also occurred. Considering that fibrotic tissue is more susceptible to shrink, the fibrosis induced by irradiation together with destruction of the squamous epithelium and vascular changes, might explain the reduction of the cyst volume and diminished fluid secretion after 90Y treatment.

[Intracystic instillation of yttrium 90 silicate colloid in cystic craniopharyngioma]

The authors evaluate the intracavital treatment with 90 Yttrium silicate colloid given in 31 occasion in 26 patients of cystic craniopharyngioma. The method has been applied since 1975 in the National Institute of Neurosurgery Budapest, using practically the same method as described by Backlund et al. (1972). Although the intracavital treatment was only one among several applied forms of treatment (resection, aspiration, shunting etc.) the effectiveness of the internal irradiation is obvious. The main effect is shrinkage of the cyst. At the 26 patients there was an average of more than 70% volume decrease of the cysts. In 5 cases the cysts totally disappeared and only on two occasions the volume has remained unchanged. Neuroophtalmological data: Preoperatively visual field defects or an impairment of visual activity have been observed in 24 out of the 26 patients studied. After the 90-Yttrium treatment the ophtalmological state of the patients improved 4, worsened in 2 cases. There was no change in 18 cases. The neuroophtalmological prognosis was good only when a relatively intact optic disc was seen; when the disc was atrophic the visual deterioration proved to be irreversible. Pathologically, the fibrotic tissue is responsible for the shrinkage of the cyst.

Further experiences in the treatment of cystic craniopharyngeomas with yttrium 90 silicate colloid

20 patients suffering from cystic craniopharyngioma were treated with intracavitary irradiation on 25 occasions. The beta emitting radionuclide 90Y silicate colloid was instilled into the cyst or cystic part of the tumour. 17 patients on 22 occasions underwent follow-up CT and ophthalmological examinations 1 to 144 (average: 34) months after the intracavitary radioisotope therapy. An 23 occasions there was an average of 82 to 90% volume decrease of the craniopharyngioma cysts. On two occasions the volume has remained unchanged and the result of the 90Y therapy cannot be evaluated yet. The neuroophthalmological prognosis was good only when a relatively intact optic disc was seen; when the disc was atrophic the visual deterioration proved to be irreversible. Pathologically, it is the fibrotic tissue that is responsible for the shrinkage of the cyst.

The radiotherapy of cystic craniopharyngioma with intracystic installation of 90Y silicate colloid

The authors describe the intracavital treatment with 90Y silicate colloid in 9 cases of cystic craniopharyngioma. The method has been applied since 1975 in the National Institute of Neurosurgery, Budapest. The intracavital treatment was only one among several applied treatment forms. In all patients a partial removal of the tumour has also been performed. The possibilities of evaluation of the effectiveness of the internal cyst irradiation are therefore limited. In most cases the intracavital treatment resulted in shrinkage of the cyst, or even was followed by its practical disappearence and the condition of the patients shows a decisive improvement. The growth of solid tumour parts is not influenced by this kind of treatment. Therefore the clinical improvement of the patient's condition depends also on the ratio between cyst and solid tumour volume. The optic nerve impairment did not improve in all cases. As a side-effect an oculomotor nerve paresis developed in several patients. Its possible explanations have been discussed, including lasting damage from tumour pressure.

Neurinoma of spinal accessory nerve. Report of two cases

Neurinomas of the eleventh nerve can be divided into intracisternal and intrajugular types. A 50-year-old woman and a 29-year-old man had neurinomas of the spinal accessory nerve in the cisterna magna which were removed at operation.

[A role of glycerol in contrast enhancement (author's transl)]

In some cases of glioma, it may be relatively difficult to demonstrate by computed tomography (CT), or even by contrast enhancement technique (CE). Studying a series of delayed CT scans, it seems that one of the main factors of delayed CE effect is due to extravascular components of iodine. So for getting better CE effect in these gliomas, we tried to increase the extravascular iodine concentration with utilizing the returning water of intravenously administrated Glycerol. By this method of drip injection of contrast material following the Glycerol, we could get an increase of CE effect of 40 or 70% comparing to the usual drip injected CE scans in two benign gliomas, but we couldn't find the difference in one malignant glioma and in the high vascular area of the benign gliomas. Though the mechanism was not completely explained in this article, we thought that CE effect in malignant gliomas or high vascular tumors was mainly by intravascular component of iodine. This malignant glioma a big cyst, and with the use of intravenous contrast material and delayed CT scanning, we had been able to know that contrast media entered cystic collections, which progressively increased in density and were maximally enhanced on delayed, 180 minutes after injection of contrast material.

Polarization microscopic investigation of subarachnoid fibrosis after subarachnoid haemorrhage

The author used the polarization microscope and topo-optical reactions such as phenol reaction, collagen-specific sulphation, and picrosirius red F 3 BA staining to investigate the nature of subarachnoid fibrosis after experimental subarachnoid haemorrhage. It is strongly suggested that the subarachnoid fibrotic deposits--which here analysed in a previous study by scanning electronmicroscopy--contain a high amount of collagen as a main component both three weeks and three months after the SAH.

Effect of antifibrinolytic therapy on subarachnoid fibrosis in dogs after experimental subarachnoid haemorrhage

The effect of antifibrinolytic therapy on posthaemorrhagic subarachnoid fibrosis was observed experimentally in dogs with the scanning electron microscope (SEM). The subchronic subjects, given intravenous injections of tranexamic acid (1 mg/day) for 12 days and sacrificed 3 weeks after cisternal blood injection, showed residual clot with thick fibrosis, especially around the haemorrhage. The chronic subjects, to which the same procedure was applied and which were sacrificed three months after cisternal blood injection, showed significant increases in the subarachnoid fibrosis, most remarkably in the parasagittal region. Tranexamic acid is widely used for preventing the recurrence of subarachnoid haemorrhage. However, it was revealed in this study that antifibrinolytic therapy might increase chronic posthaemorrhagic subarachnoid fibrosis, which is considered to be responsible for communicating hydrocephalus by disturbing epicortical CSF flow.

Scanning electron microscopy of the subarachnoid macrophages after subarachnoid haemorrhage, and their possible role in the formation of subarachnoid fibrosis

Sixty dogs with experimental subarachnoid haemorrhage (SAH), repeated SAH, and subarachnoid fibrosis (examined three weeks and three months after SAH, and treated with urokinase or dexamethasone) were examined by scanning electron microscope (SEM). The authors observed the resting and activated macrophages, the erythrophagocytosis, and giant cells in the subarachnoid space after SAH. They consider that the macrophages play an important role in the formation of subarachnoid fibrosis, similar to the role of macrophages in fibrosis in other sites.

Late post-irradiation necrosis of the brain

Three examples of late post-irradiation brain necrosis are reported. In two cases operation was performed on account of the space-occupying effects of the lesions, and in the third case the lesion was found post-mortem. The aetiology and pathology of the condition are discussed. Our findings in the three cases described are contrasted with those in 29 patients who had been submitted to similar doses of irradiation, but had not developed necrosis. The literature on pathogenesis is briefly reviewed.

The influence of dexamethasone on subarachnoid fibrosis after subarachnoid haemorrhage. Scanning electron microscopic study in the dog

The author used the scanning electron microscope (SEM) to study the influence of dexamethasone on subarachnoid fibrosis after experimental subarachnoid haemorrhage (SAH). In the subchronic group of dogs, which were sacrificed three weeks after SAH, an average of 2.82 mg/kg intrathecal dexamethasone seemed to delay the fibrosis somewhat, but statistically showed no significant difference from the control group. In the chronic group, sacrificed three months after SAH, an average of 0.95 mg/kg intrathecal dexamethasone did not prevent the fibrosis, and no significant difference was found from the untreated dogs. The author considers that steroid therapy only delays and does not diminish the inflammatory process. This may also apply to other types of arachnoiditis.

Arachnoid villi affected by subarachnoid pressure and haemorrhage. Scanning electron microscopic study in the dog

The arachnoid villi of 18 dogs were studied. The authors confirmed the pressure gradient changes of the morphology of arachnoid villi of dogs with the scanning electron microscope (SEM). A subarachnoid infusion with 5--10 times higher pressure gradient than the physiological one, tore the superficial endothelial layer from the villi, and the inner part could also be observed stereoscopically. On the surface of the arachnoid villi, the authors observed microvilli, openings of vacuoles and intercellular gaps, but did not find openings of performed channels. After subarachnoid haemorrhage (SAH) generally the villi were blocked but the authors have observed a red blood cell escaping from a villus intercellularly.